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A team of scientists is making headway in the study of bovine tuberculosis in pest species at Molesworth Station, the nation's biggest farm.

Headed by Landcare Research ecologist Dr Andrea Byrom, the project is a study of bovine TB in possums, feral pigs and ferrets in the Molesworth area, which is being used as a case study for high country regions in general.

It is expected to be completed next year.

Funded by the Animal Health Board and Landcorp New Zealand, the project forms part of the Animal Health Board's strategy to remove bovine TB from cattle and deer herds nationally by 2013.

Dr Byrom said the Animal Health Board was particularly interested in Marlborough because of its current problem with bovine TB.

As 2013 approached, areas like the northern South Island high country became more important, because, although there were fewer herds in that area, they were larger cattle herds in excellent condition with great marketing potential overseas.

"There's real marketing potential there, but this disease in New Zealand in general kind of holds us back, so it's crucial for New Zealand economically to be clear of it," Dr Byrom said.

The first step of the project, largely completed over summer, was to determine the population density of the possums in different habitats on Molesworth Station.

This involved measuring the abundance of possums and ferrets, but because of the sheer size of the station -- 183,000 hectares -- it was not possible to do vector control over the entire area, so research was targeted in high density areas.

The data is being processed, and while it is too early to report exact results, Dr Byrom said that, as expected, prolific numbers of possums had been found in areas that had a lot of briar and willows.

But a surprising result was that possums were also found to be present in the sub-alpine tussock areas and on scree slopes.

"Why would they be there? That's the million dollar question," said Dr Byrom.

Full-body autopsies were also being performed on the possums to check for the presence of the disease.

Dr Byrom said the next step of the project would involve tracking the movements of possums and ferrets in the area.

From March, radio transmitters would be placed on the animals, and this would be monitored for a year to see how movements changed through the different seasons.